Fermi LAT detection of the supernova remnant SN 1006 revisited: the south-west limb

TL;DR

This study re-analyzed Fermi LAT data for supernova remnant SN 1006, detecting gamma-ray emission from both limbs, with the south-west limb newly identified and likely dominated by leptonic processes similar to the north-east limb.

Contribution

First detection of gamma-ray emission from the south-west limb of SN 1006 using Fermi LAT data, expanding understanding of the remnant's high-energy processes.

Findings

Gamma-ray emission from the south-west limb is detected at 4 sigma significance.

The spectral energy distribution suggests leptonic processes dominate gamma-ray emission.

The NE limb's spectral results are consistent with previous analyses.

Abstract

The data from the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope have recently been updated. We thus re-analyze the LAT data for the supernova remnant (SNR) SN 1006. Two parts of gamma-ray emission from the region is clearly resolved, which correspond to the north-east (NE) and south-west (SW) limbs of the SNR. The former was detected in the previous LAT data (Xing et al. 2016), but the latter is newly detected in this work. The detection of the two limbs are at a 4 sigma significance level, and the spectral results for the NE limb is consistent with those obtained in previous detection analyses. We construct the broadband spectral energy distribution (SED) for the SW limb. Different scenarios are considered for the SED in gamma-ray energies. We conclude very similar to that of the NE limb, the high-energy and very high-energy emission from the SW limb is likely dominated by the leptonic process, in which high-energy electrons accelerated from the shell region of the SNR inverse-Compton scatter background photons to gamma-rays.